Loading...
HomeMy WebLinkAboutAPA567d1appK~.....--.y- CANDIDATE ELECTRIC ENERGY TECHNOLOGIES FOR FUTURE APPLICATION IN THE RAIlBELT REGION APPENDIX K SELECTION OF CANDrDATEELECTRIC ENERGY TECHNOLOGIES R.A.Aaberg J.C.King APPENDIX K SELECTION OF CANDIDATE ELECTRIC ENERGY TECHNOLOGIES Identification of potential candidate electric energy technologies for development of Railbelt Electric Energy Plans began with consideration of the classes of technologies which would either help offset future electric demand or which would help meet future electrical demand in the Region.Seven classes of technologies were identified,as follows: •Base load generating technologies •Cycling load generating technologies •Energy storage technologies •Fuel Saver (Intermlttent)generation technologies •Load Shaping Technologies •Electric Energy Conservation Technologies •Electric Energy Substitutes Technologies considered were limited to those directly relating to electric energy production and conservation in conformance with the scope of the study.Thus,technologies related to other energy forms were considered only to the extent that they might serve to fuel electric generating facilities,serve as energy storage media in energy storage systems which might be used in conjunction with operation of an electric utility,or that mlght serve as a direct substitute for electric energy (i.e.wood for space heati ng)• Transmission technologies were not considered,as transmission intertie alternatives will be explicitly considered in the development of alternative electric energy plans in a later task of thlS study.Technologies related to the production of fuel for electric energy generating devices were not directly conSidered,as fuel availability and price is considered in a parallel task of this study. Finally,technologies considered were limited to those normally operated in conjunction with an electric utility grid;off-grid application being outside the scope of the Railbelt Electric Power Alternatives Study. K.l TABLE K.l.Candidate Electric Energy Technologies Technology Candidate ElectrlC Energy Technology Rejected Technologies Base Load Generation Coal-Fired Steam Electric Natural Gas/Distillate-Fired Steam Electric Bl0mass-Fired Steam Electric Combined Cycle Magnetohydrodynamlc Generators Fission Reactors Fast Breeder Fission Reactors Geothermal Electric FUSlon Reactors Ocean Current Energy Systems Salinity Gradient Energy Systems Ocean Thermal Energy Conversion Systems Space Power Satellltes Cycllng Generation Combustion Turbines Diesel Generatlon Hydroelectric Fuel Cells Fuel Saver (!ntermittent Generation \~ave energy y.stems Tidal Electric Large Wlnd Energy Systems Small I'/i nd Energy Systems Solar Photovoltaic Systems Solar Central Receiver Systems Cogenerat 1 on Enercy Storage Options Pumped·Hydro . Compressed Air Storage Storage Batterles Hydrogen Storage Electric Energ~Substitutes Pas5lve Solar pace Heating ActlVe Solar Space and Hot Water Heating Wood-Flred Space Heating Total Energy Systems ElectrlC Energy Conservation BUll d1 ng Conservat i on Load Shapl ng Olrect Load Control Passlve Load Control Incentlve Prlcing Education and Public Involvement Dlspersed Thermal Energy Storage X COllll1ercial X COlllllercial X Convnercial X COllll1ercial 0 2000-2005 X COllll1ercial 0 2005-2025 X COllll1erciala2025 0 Beyond 2000 No (Resource Limited) 0 Beyond 2000 No (Resource Limited) 0 2000 No (Resource Limited) 0 Beyond 2000 No (Latitude) X Commercial X COllll1ercial X Convnercial X 1985-1995 0 1990's No (ResourCe Limited) X COllll1ercial X 1985-1990 X COllll1ercial X COllll1ercial X 1990-2000 X Commercial X Commercial (Not resolved as of this writing) X 1985-1995 (Not resolved as of this writing) X COllll1ercial X COllll1ercial X COllll1ercial (Not reso 1ved as of this writing) X COllll1ercial X Commercial X COllll1erci al X COllll1ercial X COllll1ercial X Commercial K.2 In conformance to the spirit of the study a broad spectrum of currently commercial,emerging and advanced technologies (meeting the criteria set forth above}~ere identified as potential candidate technologies.These are listed in the left-hand column of Table K.1.Nominations were based on suggestions of the contractors involved in the alternatives study,the State of Alaska, and the Project Monitor. A"technology profile ll discussing the significant characteristics of the technology was to be prepared for each candidate electric energy technology. To ensure the most productive application of study funds,candidate energy technologies were limited to those technologies haVing a reasonable probability of significantly contributing to the generation or conservation of electric energy in the Railbelt region during the planning period encompassed by this study (1980-2010).Thus,selection of candidate electric energy technologies was based on two screening criteria:Commercial availability and Techn i ca 1 feasi bil i ty. Commercial Availability.A candidate technology should be currently commercial or be projected to be commercially available by the year 2000.A technologywhich would be commercially available by year 2000 would have the potential to significantly contribute to the electric energy needs of the Railbelt prlorto the end of the planning period of this study.Projections of future commercial availability of emerging and advanced technologies are based on current developmental progress (i.e.do not assume unanticipated acceleration in the rate of development. Several potential candidate technologies do not appear to have the potential to achieve commercial maturity by the year 2000.These are .indicated in Table 1,and include Magnetohydrodynamlc Generation,Fast Breeder Reactors~Fusion Reactors,and Ocean Current Energy Systems,Salinity Gradient Energy Systems,Ocean Thermal Energy Conversion Systems,Space Power Sate 11 ites. Technical Feasibility.Candidate technologies should demonstrate reasonable potential to operate successfully in the Railbelt enVironment.As noted in TableK.1,five technologies do not at this time appear to have this potential.Four~are resource-limited,in the sense that the energy source K.3 req~ired for their operation is not available inadequate concentrations in or near the Railbelt region.These technologies include Ocean Current Energy Systems,Ocean Thermal Energy Sytems,Salinity Gradient Energy Systems and Wave Energy Conversion Systems.One technology,Space Power Satellites,does not appear to be technically feasible at the latitude of the Railbelt because of the large area of antenna required to received micro-wave power transmitted from space power satellites in geosynchronus equatorial orbit. Technologies qualltytng as candidate electrtic energy technologies are indlcated by an "X"in the second column of Table K.l.A profile has been prepared for each of these technologies and is included in the main body of this report.Technologies not qualifying as candidate electric energy technologies,for the reasons discussed above,are indicated by a "0"in the second column of Table K.l.Brief overviews of the rejected technologies are provided below. MAGNETOHYDRODYNAMICGENERATORS Technology and Siting Requirements Magnetohydrodynamlcs (MHO)is an energy conversion technology that has the potential to increase the efficiency of electrical generation plants from about 34%to 48%(Corman &Fox 1976). In an open cycle MHO generation system,fossil fuel is burned at a sufficiently high temperature so the product gases are ionized (4000.,.5000 0 F).Electrical conductivity of the hot gases is increased by "seeding"with readily ionized material (salts of cesium or potassium). When passed through a magnetic field,this produces an electric current in the gas.The current (DC)can be removed directly with metal rods or "electrodes.1I The DC output of the MHO channel is converted to ac in solid state inverters (Corman &Fox 1976).The gases exit through a series of heat exchangers and a steam generator,which drwes an AC generator. Seed materlal K2C0 3 is used to bothlncrease conductivity and tie up sulfur asK2S0 4 •The seed recovery system and integral clause plant converts K2S0 4 to seed material plus elemental sulfur.Problems which may K.4 delay implementation of MHO technology include predicted poor forced outage rate,short "I ifeexpentancy,i nflexi ble operation (diff1cul t at mi nimum load), difficult operation and control,corrosion problems,poor potential for retroflt (Corman and Fox 1976). Current Status of Development A 250 hr test of a 200 kW system was run successfully in 1978 (Energy Dally 1978)at AvcoEverett Research Laboratory in Everett,Massachusetts.A coal flred power plant with a demonstration open-cycle MHO generator is under construction in Butte,Montana. It wasestimatedi n 1976 that a commerci al MHO facil i ty could be operational by 2003 (Corman and Fox 1976).In an International Energy Agency study,the reference start year for a coal-fired MHO electric power plant was 2005 (lEA).However,funding of MHO has been cut from $60.5 million in FY 1981 to zerO 1n 1982.Confirmation of the engineering feasibility of MHO and corrmercial demonstration will become the responsibility of the industry (DOE 1981). Applicabil1ty to the Railbelt Region The time scale for development of commercial MHO conversion systems is not consistent with the time frame of the Alaska Railbelt Electric Alternatives study. An open cycle MHO facility would be located at a large central fossil-fired power plant.Gaseous emissions of NO x and SOx are estimated to be substantially less than those from a conventional coal-fired power plant (Corman and Fox 1976).A MHO facil ity 1S estimated to consume only 60%as muCh make-up water as a conventional steam plant,and use less than 40%of the tota 1 water requi rement of a convent i ana 1 plant (Corman and Fox 1976). FAST BREEDER FISSION REACTORS Technology and Siting RegUirements A fast breeder reactor (FBR)is a facil1ty designed to generate electricity by using the heat produced by controlled nuclear fission of plutonium.A breeder produces more plutonium from uranium than it consumes. K.5 When isotope 238U (which constitutes 99.3%of natural uranium)in the fuel absorbs a neutron,it decays to 239pu,which is the main energy source for the breeder.The heat generated by fission is removed by the liquid sodium coolant in the primary loop.Heat is exchanged to an intermediate sodium loop.From the intermediate coolant loop,heat is exchanged to water coolant in the steam generator.At that stage,the steam cycle is similar to that of any other conventional thermal power plant (fossil or nuclear). The overall thermal efficiency of an fBR is slightly higher than that of a light water reactor (LWR)because it operates at higher temperature.The product ofa comercial breeder facility would be about 1000 MWe,baseload power. Siting considerations are.the same as those for conventional nuclear plants.These include adequate water available for cooling,geologic and seismic stability,and 100-400 acres of land remote from a large population center.In addition,access to reprocessing facility is required by an FBR. Impacts from a breeder plant,like any large thermal power plant include local impacts during construction,heat release to the environment and fog created by cooling towers. A pr1ncipal problem for breeder development 1S 1n the fuel cycle. Reprocessing and fabrication facilities for breeder fuel must be built for cont1nuing breeder operation.Fuel reprocessing provides for recovery and purificaton of plutonium contained in the spent fuel,so it can be recycled. Fuel fabrication prepares the recovered fuel for recycle in a power plant. Current Status of Development Current U.S.experience with breeders1s being acquired at the Fast Flux Test Facility (FFTF)which achieved full power in December 1980 •.The reactor capacity is 400 MW thermal,approaximately equivalent to 133 MWe,but is not being used for generation of power.The Clinch River Breeder Reactor (CRBR) will generate 350 MWe.The CRBR has been restored to the FY -1982 DOE budget (DOE 1981). The conceptual Design Study reactor (COS)is a 1000 MWe gross facility. The proposed schedule calls for completion in 10 years.A 1200 MWe commercial K.6 prototype reactor is expected to be operational about 2001,with the first commercial plant to be in the 2006-2023 time frame (DOE 1979). Applicability to theRa il be 1tRegi on Breeder reactors will not be established on the commercial market by the year 2000,and are thus out of the time consideration of this project. FISION REACTORS Technology and Siting Requirements Fusion power results from the conversion of mass into energy when two light nuclei-collide and combine IIfuse u to become a single,heavier atom.The heavy 1 sotopes of hydrogen,deuteri urn (0)and triti urn (T)are emp loyed in DT --~--- fusion,the first likely corrmercial candidate.The reaction is as follows: iD +iT+plasma energy ;He +6n +fusion energy Deuterium is present in water in sufficient quantities to be available for millions of years.The other fuel atom,tritium,is created by neutron capture ina lithium blanket region surrounding the fusion reaction chamber (Dlngee 1979). The heat produced would be used with conventional steam generation (Dingee 1979)via an intermediate heat exchanger or possibly closed-cycle MHO.FuslOn power plants are projected to be large,1000 MWe for example,and would be operated as base loaded facilities.Siting considerations are slmilar to those for a conventional LWR fission plant.A site should be near a load center,with cooling water available,satisfactory geology and seismology,transportation facilities toburlal site for solid radioactive wastes.In addition,large land area is required to preclude effects on the public of magnetic fields,and interference on electrical and communication systems. The inventories of tritium would be greater than for present fission designs (Strand and Thompson 1976).Consequently,some tritium is anticipated to escape the plant in both llquid and gaseous effluents. K.7 Because of the high temperature involved,fusion plants may be more efficient than present LWRs.But large heat releases and fog created by cooling towers may have significant impact on the siting of the plant. Current Status of Development Energy breakeven requires the product of confinement time (sec)and density (ions/~c)to be greater than 200 trillion at a temperature over 100 mi 1l1onoF.No fusi on device has yet to reach "breakeven"--where fusion energy release is just equal to the energy supplied to run it.It is expected thatbreakeven will first be reach by Tokamak Fusion Test Reactor sometimes in 1983 (Blake,1980). Applicability to the RailbeltRegion This time scale is not consistent with the Railbelt Electric Energy Alternative Study. OCEAN CURRENT ENERGY CONVERSION Technology and Siting Requirements There have been a number of proposals for the extraction of power from ocean currents.These are,in principal,relatively simple installations--such as turbines and paddle wheels (Isaacs and Schmitt 1980). DOE has supported preliminary studies of a large ducted turbine for ocean current energy conversion.The device is an undersea,moored,ducted turbine, driven by current flow kinetic energy,which drives electrical generators and transmits power to shore with a sea-floor cable.The structure envisioned is on the order of 200 to 300 feet in diameter,and has a rotational speed of 1 RPM.The proposed structure would be of hollow aluminum construction.An individual unit would provide 75 MWe (Lissaman et al.1980).The designers of this device have proposed moonng 132 such turbines in the Florida current to deliver 10,000 MWe to the Florida power grid. The Florlda current of the gulf stream is the only candidate for U.S. Production of Energy from ocean currents (Booda 1978).Even a major current has very low energy density,equivalent to about 5 em of water head,or about 1000 times lower than for thermal gradients.The Florida current runs at K.8 about 2.&to 2.9 knots off Miami,whereas the Alaska current runs at 1 knot (U.S.Department of the Interior 1970).Since kinetic energy is proportional to the square of velocity,the Florida current energy density is approximately 6 to 8 tlmes that of the Alaska current. Status of Development The preliminary design study of ocean current energy conversion was funded by DOE.The study calculated turbine and power extraction performance, and tested a I-meter rotor model (Lissaman et ale 1980). In 1980 it was projected that ocean turbines could be commercialized by 1999.However,that assumed that DOE funded work would continue and a full-scale prototype would be complete in 1985.Since Ocean Energy systems has no funding for FY1982 and beyond (U.S.DOE 1981)the development of ocean current energy conversion is in doubt. Applicability to the Railbelt Region The future of ~cean current power in the U.S.is uncertain at this time. Apparently,it will not be commercial in the U.S.by the year 2000,which puts 1t out of the time scale of this study.If ocean current energy conversion were cornnercial,Alaska would not be a good location for a facility, considering the very low energy density of the Alaska current. SALINITY GRADIENT ENERGY CONVERSION TECHNOLOGY AND SITING REQUIREMENTS Salinity gradient energy conversion is a large potential source of power.The concept involves converting the energy of mixing of high and low saline waters into usable energy. The energy density of this process 1S equivalent tdabout 240 m of water head,(equivalent to an OTEC Plant with a temperature difference of 23 0 F) (Isaacs and Schmitt 1980).The energy available represents a theoretical power of 2MW for a flow rate of 1 m 3jsec for a freshwater river flowing into the sea (Olsson,Wick and Isaacs 1979). There have been three approaches for extracting power from salinity gradients:1)osmotic exchange against a hydrostatic pressure (or K.9 pressure~retarded osmOSiS};2}the dialytic batter {inverse electrodialysis) (Isaacs and Schmitt 1980);and 3)vapor exchange between two solutions (i nverse vapor). Pressure-retarded osmosis uses the osmotic pressure gradient (about 23 atm)across a semipermeable membrane which separates seawater (at 35 parts per thousand salinity)and freshwater.To convert the osmotic pressure,one releases the pressurized solution through a hydroturbine (McCormick 1979). This concept requires large amounts of fresh water,and must be sited at a river. The dialytlc battery is made of anionic-permeable and cationic-permeable membranes in a battery type container.Salt water is passed between alternate membrane pairs,while fresh water separates one pair from another.Positive and negative charges are transferred to electrodes at the ends of the membrane stack.A 100 watt model has been studied (McCormick 1979). Inverse vapor compression involves vapor exchange between two solutions, prefereably at elevated temperatures.Due to lower vapor pressure of salt water,water vapor wi 11 transfer from fresh water to salt water in an evacuated chamber.Power can be extracted if a turbine is placed in the vapor flow between the two solutions (Olsson,Wick and Isaacs 1979). The third scheme uses no membranes,but only heat exchangers and turbi nes.Vapor pressure differences increase dramati ca 11y with temperature, so a low-grade source of heat would be advantageous.Power is required to create and maintain a vacuum in the chamber (Olsson,Wick and Isaacs 1979). The energy density ofa salinity gradient is a function of the concentration differences.The energy density of a system of saturated brine (260 parts per thousa.nd)and fresh water is about 20 times greater than a seawater (35 parts per thousand)and fresh water system (Isaacs and Schmitt 1980)• Energy densities for Alaskan salinity gradient resources would be slightly lower than values presented because lower salinity of the sea water. K.10 The salinity of sea water off alaska is 31.5-32 parts per thousand most of the year (U.S.Department of the Interior 1970,p.83)about 10%less than salt water in the referenced experiments. Status of Development Salinity gradient energy conversion is in the experimental stage. Salinity gradient research was conducted by DOE Under Ocean Energy System, which will no longer be funded as of FY1982 (U.S.DOE 1981).Therefore,the commercialization of this technology is uncertain at best. Applicability to the Railbelt Region Considering the current low state of development of salinity gradient energy conversion technology and the funding situation,this will not be an optlon in the time frame under consideration to meet Railbelt power requirements. SPACE PWER SATELLITES Technology and Siting Requirements The space power satellite (SPS)concept is based on large (5 km x 10km) solar collectors in geostationary orbit that transmit power to a receiving antenna (rectenna)on the earth.The rectenna would consists of an array of inclined planar solar panels 3m wide in long continuous TOWS.Power is converted from DC to AC and stepped up to 500 kV for transmission (Brown et al.1980~~.328).The microwave power transmission link cannot be scal~d down economically to powers less than a gigawatt (1000 megawatts)(Sperber and Drexler 1980).The conceptual design of a satellite power station developed in the DOE/NASA Concept Development and Evaluation Program (1977-1980)calls for capacity of 5 gigawatts. The rectenna requires a large area of relatively flat land with an area of low population density.Variables which exclude rectenna siting include inland water,military reservations,population density,marshland,or perennially flooded areas,interstate highways and unacceptable topography. Potentlal exclusion areas include Indian reservations,and national interest lands.Other variables which impact design and cost of the rectenna site K.l1 include snowfall,freezing rain,sheet rainfall,wind,lightning density, hail,seismic rlsk,timbered areas,and water availability (Ankerbrandt 1980, p.127). The Ground Receiving Station (GRS)should be near the load center,but located to avoid radio interference.An optimum location would be a desert area.A prototype assessment of environmental impact of siting and construction of a GRS Used the California desert about 250km north of Los Angeles for baseline data (Bachrach 1980,p.525). The land area required is i;lbout 400 km 2 at 35 0 latitude.At the latitude of the Railbelt area,about 63 0 ,an area of about 1200 km 2 would be needed (Reinhartz 1980).Construction of a Ground Receiving Station in a desert area at 36 0 is expected to require 25 months,with an average work force of 2500.ApprOXimately 450 workers would be required for 24-hours,365 days per year operation (Bachrack 1980,p.525).A GRS facil ity in more difficult terrain that covers three times the area may then require a construct10n work force of 7500 or larger,and an operations crew of 1350. Construction of a GRS facility would displace existing land uses,totally disrupt the ecology of the site,and have great socioeconomic impact from the immigration of construction workers.The most significant environmental issue from satellite power transmission 1S long term exposure to low level microwaves on telecommunication,particularly interference with defense requirements (Valentino 1980). Current Status of Development The objective of the DOE/NASA sponsored SPS program is lito develop by the end of 1980 an initial understanding of the technical feasibility,economical practical i ty,and the soci eta land environmental acceptabil i ty of the SPS concept II (Glaser 1980).The technology will not be developed for at least 10 years,and commercialized in no less than 20 years (Glaser 1980).The conceptual Development and Evaluation Study gUidelines call for initial commercial operation of power satellites in the year 2000 (Schwenk 1980).The SPS assessment program has been completed,and the program is closed.There is noSPS funding for TY1981 or FY1982-(Riches 1981).Principal problems requiring resolution include solar cell conversion efficiency and cost,, K.12 microwave power transmission,space transportation,and construction operation,maintenance and active control of the SPS structure (Schwenk 1980)• Prospects for Railbelt Application An SPS system does not currently appear to be a candidate technology for supplying power to Alaska for several reasons: •The time scale for development is uncertain;funding has been discontinued indefinitely. •The projected size of generation system,5 GWe (5000 MWe)is much larger than demand forecasts for the Railbelt region. •The northern latitude location of the Railbelt region requires a much larger rectenna area and lower power density than a more southerly site,which makes the system even less cost-effective. OCEAN THERMAL ENERGY CONVERSION Technology and Siting Requirements Ocean thermal energy conversi~n (OTEC)uses the temperature difference between surface water and ocean depths to generate electricity.A conventional thermodynamic cycle is used with ammonia or propane as the working flUid.The working fluid is boiled by the warm sea water,the vapor is run through a turbine where power is extracted,the fluid is cooled by cold deep-ocean water,and is pumped back to the·warm water heat exchanger. The efficiency of the system is based on the difference in temperature between shallow and deep water.Surface water in the tropics is heated by the sun to about 79 to 84 0 F.Cold water from about 3000 to 6000 feet deep on gi nates in the Arcti c or Antarctic,and has a temperature of 39 to 44 0 F (Hooda 1978). The efficiency of the OTEC closed-cycle is limited by Carnot efficiency of a heat engine.The ideal heat engine working at upper and lower temperatures of 80 0 F and 40 0 F (540 0 R and5000 R,respectively)would have an efficiency of 650-500/540,or 7%.Real equipment with friction and K.13 pumping losses would have efficiency of about 3%.A 100 MW plant would have to pump 30,000 cubic feet of sea water per second (Forbes et al.1979). OTEC powerplants are suitable for tropical or subtropical seacoasts or offshore regions.A minimum temperature difference of about 30 0 F and depth of about 2000ft is required.DC power would be transmitted to the load center by undersea cables.The proposed size ofa commercial OTEC plant is about 200 to 400MW (Richards 1979).Potential impacts include interference with ocean transportation,flsheries and sea life,and influence on natural ocean circulation. Status of Commercial Development A demonstration of the feasibility of OTEC has been performed by OOE. The DOE budget for OTEC ha~been reduced from $34.6 million in FY81 to zero in FY82.DOE considers it the responsibility of the private sector to develop marketable systems once technical feasibility is established (U.S.DOE 1981). A commercial prototype OTEC powerplant was envisioned about 1990 (Richards 1979).The reference start year for a commercial operation a 100 MWe ocean thermal gradient electric powerplant was taken to be 2000 in an International Energy Agency study (lEA 1980).The commercial sector will determine the actual development schedule for OTEC. Railbelt Feasibility Sites for OTEC plants are generally restricted to 20 0 north and south of the equator (Booda 1978).OTEC power cannot be considered in alaska because the concept depends on warm (80 0 F)tropical ocean surface temperatures.The mean surface temperature off the south coast of Alaska varies from 42 0 Finwinter to 54 0 F in summer (U.S.Department of the I nten or 1970 ,p.83). OCEAN WAVE ENERGY SYSTEMS Technology and Siting ReqUirements Many methods of ocean wave energy conversion have been suggested.Most of these methods fall into the follOWing categories:1)heaving bodies, 2)pitchlng or rolling bodies,3)caVity resonators,4)wave focusers, K.14 5)pressure converters,6)surging bodies,7)flapping bodies,8)rotating outriggers,and 9)combinations of the above (McCormick 1979).DOE sponsored efforts include a full-scale wave energy conversion program with the International Energy Agency (lEA).The apparatus,known as "Kaimei,"is a cavity resonator system.There are three air turbines on the deck of Kaimei which have been designed and constructed in Japan,the United Kingdom,and the United States.The turbines are excited by the air motions above the rising and falling of the surface of the water.Each turbo-generating system is designed to deliver 125 kW in a 2 meter sea with a period of 6 seconds (McCormick 1979). Another DOE-sponsored effort has been in wave-focusing systems.Wave focusing is accomplished by four techniques:1)radientwave interaction, 2)Fresnel-type focusing,3)refraction,and 4)channeling. Radient wave interaction occurs when a body is in resonance with the incident wave.Fresnel-type focusing is done by a lens type structure which causes wave diffraction or refraction.A refraction wave energy device called DAM-ATOLL,was developed at Lockheed.The device is a submerged dome which causes incident waves to refract and focus on a vertical axis turbine located at the center of the dome.The device,a lenticular hump on the sea floor, could be produced by dredging or dumplng (Isaacs and Schmitt 1980). Wave focusing by converging channels appears to be feasible only in or near the surf zone where energy is relatively low.Thus,DOE Has not sponsored studies in this area {McCormick 1979).The U.S.wave energy program has concentrated on wave focusing systems and the cavity resonator because larger structures are not justified by the low energy density.Also,large structures undergoing significant motions while moored at sea is contrary to standard ocean engineering practice (McCormick 1979). Wave energy denSity has been estimated to be equivalent to 1.5 meters of water head.This compares with 570 meters for OTEC,with a 36 0 F temperature difference (Isaacs and Schmitt 1980).Siting requirements will include location in the ocean with consistent waves,near a load center.Such a facility would probably be used as a"fuel saver." K.15 I .¥ The DOE considers only the northern half of the Pacific coast a promising area.It is estimated that between 5 and 50 megawatts per kilometer of coastline could be generated (Booda1978).The northern California and Oregon coasts have waves of height 5 feet and over 20 to 30%of the time in spring and winter,and 30 to 40%of the time in summer and autumn.Off the Alaskan coast,the frequency of waves of heightS feet and over varies from less than 5%in the spring to 10 to 20%in the fall (U.S.Department of the Interior 1970). Status of Commercial Development Currently,wve energy systems are in the developmental stages.Problems requiring resolutin include the need to withstand large storm waves,corrosion and fouling,energy storage and/or transmission,capital costs of fabrication. and installation (Forbes et ale 1979). An International Energy Agency study assumed 1990 as the reference starting year for convnercial operation of a 2 MWe wave powerplant (lEA 1980). Wave energy research programs have been supported by DOE and are dependent on government funding.Wave energy studies have been about 4%of ODE's Ocean Energy systems budget.Since Dcean energy systems will not be funded in FY1982 (U.S.DOE 1981),the fate of wave energy development is uncertain. Applicability to the RailbeltRegion The coast of Alaska is not an optimum location for wave energy powerplants,as shown by wave height/frequency statistics.In addition,the development of wave energy technology is uncertain,and may not be available in the time frame under consideration. K .16